The danger of solar storms
Solar activity oscillates between minimums and maximums on an 11-year cycle, and the Sun is currently beginning its "climb" toward the next maximum in 2011 or 2012. As the Sun gets closer to its maximum, the likelihood of major storms increases.
The two kinds of solar storms experts are concerned about are solar flares and coronal mass ejections. Solar flares appear as explosive bright spots on the surface of the Sun, which is about 93 million miles from Earth. The flares occur when magnetic energy built up in the solar atmosphere near a sunspot is suddenly released in a blast of radiation and electrically charged particles.
A coronal mass ejection (CME) is, according to NASA, the "violent eruption of a huge magnetic cloud of plasma from the Sun's outer atmosphere." The plasma from a CME — typically more than 10 billion tons of partially ionized gas — travels thorough space at several million miles per hour. A CME cloud can hit the solar wind — electrons and protons that normally stream from the Sun — and accelerate those particles into a high-speed shock wave. If a CME happens on the side of the Sun facing Earth, the shock wave can collide with Earth's magnetic field. This impact can dump about 1500 gigawatts of electricity into the Earth's atmosphere, twice the generating power of the entire U.S. electrical system.
Extreme CME's can destroy the electronics in orbiting satellites, including those that provide data for all of our GPS devices. At the surface, extreme CME's change the strength of the Earth's magnetic fields in ways that can trigger massive power surges that blow power transformers and damage electrical grids. These power surges can even create corrosive electrical currents in gas and oil pipelines. —Jim Dawson
For more information:
The Space Plasma Research Group at the University of Minnesota has created a web page to guide people in viewing and understanding both aurora and space weather. The page, Aurora Borealis in Minnesota, can be found here.
A video about space storms can be found here.